JPS63251655A - Continuously variable transmission of multiple belt type - Google Patents

Abstract

PURPOSE:To prevent a V-shaped block from breaking due to a large herz stress acting on the V-shaped block by making the end surface of each of the V-shaped block facing the side surface of a V-groove of a pulley curved so that each of the V-shaped block comes into contact with both of the side surfaces of the V-groove at one point for each of the side surfaces. CONSTITUTION:Multiple V-belts 13, 14 stretched in plural number between common V-groove pulleys 11 and 12 transmit power between the common V- groove pulleys 11 and 12 by means of frictional engagement between the V-shaped blocks, 19, 20 and the side surface 15a-18a of the V-groove of a pulley. Continuously variable speed change is possible in this case by displacing a V-groove surface of one of the V-groove pulleys 11, 12 in the axial direction thereby changing the arc radiuses of the belts 13, 14 routed over the pulley. The end surfaces 19a, 20a of the V-shaped blockes 19, 20 facing the side surfaces 15a-18a of the V-groove of the pulley are curved with a curvature radius smaller than the minimum curvature radius of the corresponding side surface of the V-groove within a plane containing the rotary axis 0 of the pulley. As a result, the end surfaces 19a, 20a of the V-shaped block come into contact with the side surfaces 15a-18a respectively only at one point.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a multi-belt type continuously variable transmission in which a plurality of belts are multiplexed between common V-groove pulleys in order to increase transmission capacity. be.

(Prior technology) This type of continuously variable transmission is published in the monthly magazine "Motorfan".
A device as shown in FIG. 7 can be considered, which is an application of the Kanesaka type belt transmission means described on page 178 of the December issue of 1988.

In the figure, 1 is a torque converter, 2 is a double pinion type planetary gear set, 3 is a forward clutch, 4 is a reverse brake, 5 is an input shaft, 6 is a capebelt transmission means, 7 is an output shaft, 8
9 is the counter gear set, 9 is the final drive gear set, l
O indicates a differential gear, respectively. The engine power that has passed through the torque converter 1 reaches the input shaft 5 as it is via the planetary gear set 2 when the forward clutch 3 is engaged, and is reversed by the planetary gear set 2 when the reverse brake 4 is engaged and reaches the input shaft 5. Power to the input shaft 5 is transmitted to the output shaft 7 by the hook-and-loop belt transmission means 6, and then passes through the counter gear set 8 and the final drive gear set 9 to the differential gear 1o, allowing the vehicle to move forward or backward.

The transmission means 6 includes a groove boot 1 and a groove pulley 12 on a shaft 5.7, and two V-belts 13. between these pulleys.
The pulleys 11 and 14 are arranged in multiple layers, and each pulley 11 and 12 is connected to one flange 15 to enable continuously variable speed.
．． 16 is fixed, and the other flanges 17 and 18 are adjustable in position in the axial direction as shown by two-dot chain lines. For shifting, the movable flange 17 is displaced, for example, from the solid line position to the two-dot chain line position, and the movable flange 18 is correspondingly displaced from the solid line position to the two-dot chain line position. This allows both ■
The state in which the bells) 13 and 14 are wrapped around the pulleys 11 and 12 is changed from the one-dot chain line state to the two-dot chain line state in FIG. 8, and a continuously variable speed can be performed.

(Problems to be solved by the invention) By the way, in order to ensure the strength of the V-belts 13 and 14,
When using a V-belt formed by attaching a large number of ■-shaped blocks sequentially in the longitudinal direction to an endless flexible body, the flange 15.
Side surface 1 of pulley V groove formed by 17 and 16.18
5a, 17a, 16a, and 18a must be curved in a plane that includes the pulley rotation axis, as will be explained below, resulting in a problem that will be described later.

First, to explain the reason why the pulley ■groove side surfaces 15a to 18a are curved, the pulley-wrapping arc diameter RI m + RZ a + RI b + of the V-belt 13.14 shown in FIG.
R2b is the distance between the input and output shafts 5 and 7, which is C (for example, 2
45. OOmm), the circumferential length of the V-belt 13.14 is Lb, (e.g. 856.56mm), L, 2 (e.g. 1
032.43), change the gear ratio to ip (e.g. 2.5 to 0
．． 4), it is expressed by the following equation.

R1fi=2(i,+1)” Rzi=R1mX ip
...(2) R1b= 2(ip+1)" Rzb=R+i+X ip
...(4) The difference in the winding arc diameter of the V-belt between the inner and outer circumferential V-belts determined by these formulas is shown in Figure 9 as Δ
As shown by R1 and ΔR6, the width of the ■-shaped block 19.20 forming the inner and outer peripheral V-belt 13.14 is also (for example, 30.0
Omm), -5□ (for example, 40.88mm) is constant, so it increases as the wrapping arc diameter increases (
ΔRh〉ΔR,). Therefore, the inclination angle of the plane passing through the end face of the ■-shaped block 19, 20 in the common plane containing the pulley rotation axis is α7. As shown by α, it decreases as the wrapped arc diameter increases. Pulley according to this angle of inclination■
Since the groove side surfaces 15a to 18a need to be inclined, they must be curved in a plane that includes the pulley rotation axis.

However, due to the curvature of the sides of the pulley ■ groove, the ■ shaped blocks 19 and 20 each have two end faces as shown in FIG.
The pulley V-groove side surfaces 15a to 18a are exposed to a large Hertzian stress during power transmission, resulting in a significant loss of durability or damage.

(Means for Solving the Problems) In view of the above-mentioned problems, the present invention has been developed by changing the end face of the ■-shaped block opposite to the side surface of the pulley groove to the minimum curvature of the corresponding pulley groove side surface in a plane including the pulley rotation axis. It is curved with a radius of curvature less than the radius.

Ru.

(Function) A plurality of V-belts stretched between the common ■groove pulleys transmit power between the common ■groove pulleys through frictional engagement between the ■shaped block and the side surface of the pulley ■groove. During this time,
Continuously variable speed is possible by displacing one V-groove side surface of each V-groove pulley in the axial direction and changing the arc diameter around which each belt is wound around the pulley.

By the way, since the end face of each ■-shaped block facing the side surface of the pulley ■ groove was curved with a radius of curvature that was less than the minimum radius of curvature of the corresponding pulley groove side surface in the plane that included the pulley rotation axis, each ■-shaped block Pulley with only one end face ■
Since it comes into contact with the side surface of the groove, it is possible to prevent large Hertzian stress from acting on the ■-shaped block, improve its durability, and prevent damage.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 are examples of measures taken by the present invention for a multi-belt type continuously variable transmission similar to those described above with reference to FIGS. 7 to 10, but in this example, the V-belts 13 and 14 are 2
As shown in the figure. That is, a large number of parallel bins 21 are connected to each other by link plates 22 to form a chain-type endless flexible body 23, and ■-shaped blocks 19 (20) are sequentially fitted into this in the longitudinal direction. ■Bell) 13
(14) is constructed. Therefore, the width of the ■-shaped block 19 on the inner peripheral side ■belt 13 is also the same.

As shown in FIG. 2(b), the outer peripheral side of the belt 14 is shown in FIG.
) The width of the ■-shaped block 20 shown in ) is also made smaller than 2, and the circumferential length of the inner V-belt 13 is made shorter than that of the outer V-belt 14, so that both ■-shaped blocks 13 and 14 are made as shown in FIG. As shown in Fig. 1 (it can be wrapped around the V-groove pulleys 11 and 12 multiple times).

In the present invention, as shown in FIG. 1, the radius ρ.

End faces 19a, 20a of each ■-shaped block 19.20 facing the pulley groove sides 15a to 18a curved at ρ2
In the plane including the pulley rotation axis 0, the corresponding ■
Radius of curvature less than the minimum radius of curvature of the groove side surface RVII Rv2
Curve it with.

Thereby, the end face 19a of each V-shaped block 19.20.

20a comes into contact with the corresponding ■groove side surface at only one point, no matter what the wrapping arc diameter of the V-belt 13, 14 is. Therefore, it is possible to prevent large Hertzian stress from acting on the ■-shaped blocks 19 and 20, thereby improving their durability and preventing them from being damaged.

By the way, the end face curvature radius RVI+1 of the V-shaped block? v
If z is made too small, the V-shaped block end face 19a.

The contact area between the pulley 20a and the corresponding pulley groove side surface becomes small, resulting in an increase in surface pressure, resulting in a disadvantage in terms of durability. In view of this fact, in the present invention, the ■-shaped block end face 19
Confirm that it is best to determine the radius of curvature of the end face of the ■-shaped block RVl + RV□ so that 20a contacts the side surface of the pulley groove over a range of about one-third of the height of the ■-shaped block E9, 2o. Ta.

As described above, the outer V-belt 14 is larger in width and circumference than the inner V-belt 13, and is greatly influenced by the center force during transmission. Therefore, the belt 14 becomes larger (elongated) than the belt 13 during power transmission, and this difference causes a situation where only the V-belt 13 transmits power, which tends to reduce the durability of the V-belt 13. Therefore, in this example, as is clear from the comparison between FIGS. 2(b) and 2(c), the cross-sectional area '4z x H2 of the endless flexible body related to the outer peripheral side ■belt 14 is calculated from the inner peripheral side ■belt. The cross-sectional area of the endless flexible body related to 13 is made larger than the cross-sectional area wl be smaller than that of According to such measures,
Even if the V-belt 14 on the outer circumference side receives a larger centrifugal force than the V-belt 13 on the inner circumference side, the outer circumference side ■
It is possible to prevent the belt 14 from being stretched significantly more than the inner V-belt 13. Therefore, the inner circumferential side ■
, it is possible to avoid a situation where only the belt 13 transmits power, and it is possible to prevent a decrease in the life of the inner peripheral side belt 13.

In addition, in making the elongation elastic modulus of both belts 1-13 and 14 different, the ratio is determined by the weight ratio per unit length of the belt and the running radius ratio of the input pulley or output pulley in the entire gear ratio range. The value is approximately the same as the product of the average value of We have confirmed that it is best to set the product to approximately the same value.

The idea of making the elongation elastic modulus different between the inner V-belt and the outer V-belt as described above is shown in FIG. 4(a).

As shown in (b) (also when the endless flexible body 23 is constructed by laminating a large number of steel belts 24, LX H+< h,
Needless to say, it can be applied directly to X112. However, in this case, it is preferable that the elastic modulus of elasticity of each V-belt is made smaller as the steel belts are located on the outer side, as shown by the arrows in FIG.

Next, to explain the lubrication system of V-belts 13 and 14,
Since the outer V-belt 14 runs faster than the inner V-belt 13, it requires a larger amount of lubricating oil.

In view of this fact, a lubricating pipe 25 for the inner V-belt 13 and a lubricating pipe 26 for the outer V-belt 14 are arranged, for example, at the positions indicated by X and Y in FIG. 8, as shown in FIG. are provided separately. These pipes 25, 26 are connected to a common hydraulic power source 27 to supply the corresponding V from the nozzles 25a, 26a.
Lubricating oil is spouted onto the inner circumference of the belts 13 and 14, and orifices 28 and 29 are installed in both pipes 25 and 26, so that a large amount of lubricating oil is supplied from the inner V-belt 13 to the outer V-belt 14. so that

Next, considering the arrangement pitch of the V-shaped blocks shown by P in FIG. When the arrangement pitch of the blocks 20 is large, the two blocks' interlocking one-stroke components approach or synchronize, and the sound pressure level for that frequency is amplified as shown by [ in Fig. 6, and the noise peak f is It gets expensive. Therefore, in this example, the arrangement pitch of the V-shaped blocks 20 related to the outer circumferential side V-belt 14 is set to the ratio of the arrangement pitch of the ■-shaped blocks 19 related to the inner circumferential side V-belt 13 to the running radius of the bells 13 and 14 (Rb /Ra) is smaller than the double value, or simply the inner circumferential side V
The arrangement pitch of the ■-shaped blocks 19 related to the belt 13 should be less than or equal to the arrangement pitch.

In this case, one blowing component of the pulley mesh of the ■-shaped block 19, 20 will be separated, and the sound pressure level for that frequency can be lowered as shown by g in FIG.
Noise peak g++ gz can be kept low.

(Effects of the Invention) As described above, the multiple V-belt type continuously variable transmission of the present invention has the end face of each ■-shaped block facing the pulley V-groove side surface within the plane containing the pulley rotation axis, and the corresponding pulley ■ Since it is curved with a radius of curvature that is less than the minimum radius of curvature of the groove side, each ■-shaped block comes into contact with both sides of each ■-groove pulley at one point, which prevents large Hertzian stress from acting on the ■-shaped block. This can improve durability and prevent damage.

[Brief explanation of drawings]

Figure 1 is a schematic side view of the pulley section of the multiple V-belt type continuously variable transmission of the present invention, Figure 2 (a) is a cutaway side view of the main part of the V-belt used on the same side, Figure Φ), (C ) are cross-sectional views of the inner circumferential side V-belt and the outer circumferential side V-belt on the line ■-■ of FIG. 3(a), respectively.
The figure is a diagram showing the elongation elastic modulus of the inner and outer V-belts. Figures 4 (a) and (b) are similar to Figures 2 (b) and (C) showing other examples of the inner and outer V-belts. Figure 5 is a diagram showing the elongation elastic modulus of the steel belt in the same ■ belt. Figure 6 is the sound pressure level line when the ■-shaped block arrangement pitch of the inner and outer V-belts is the same and when it is different. Fig. 7 is a route diagram showing the general structure of a multiple V-belt type continuously variable transmission, Fig. 8 is an explanatory diagram of the state in which the V-belt is wrapped around the boob, and Fig. 9 is a state in which the side surface of the pulley groove is curved. An explanatory diagram, FIG. 10, is an explanatory diagram showing a problem caused by this curved pulley groove side surface. 11.12...■Groove pulley 13...Inner circumference side V-belt 14...Outer circumference side V-belt, 15.16...
・Fixed flanges 17, 18...Movable flange 15a
~18a...V-groove side surface 19.20...■-shaped block 19a, 20a...■-shaped block end face 23...Endless flexible body 25.26...Lubrication pipe 27...
・Hydraulic power source 28. 29... Orifice 'Gumini E■婉zut-'gu → Upper koshiki■婉犀1- Fig. 4 (a) 23 (P, 11fi town bending a) (b) '23 (indication 111is 2Tm#) Figure 6

Claims (1)

[Claims] 1. A plurality of V-belts each having a large number of V-shaped blocks sequentially attached to an endless flexible body in its longitudinal direction are strung between common V-groove pulleys, and the V-belts of the pulleys are V power is transmitted through frictional engagement between the groove side surface and the V-shaped block, and one V-groove side surface of each V-groove pulley is displaced in the axial direction to change the pulley-wrapping arc diameter of each V-belt. In a multiple V-belt type continuously variable transmission in which V-shifting is performed, each V-shaped block is in contact with both V-groove sides of each V-groove pulley at one point, so that The end face of the V-shaped block is in a plane that includes the V-groove pulley rotation axis,
A multiple V-belt type continuously variable transmission characterized in that the end face of each V-shaped block is curved with a radius of curvature that is less than the minimum radius of curvature of the side surface of the V-groove.
2. The multiple V-belt type continuously variable transmission according to claim 1, wherein the V-groove side surface is in contact with the V-groove side surface over a range of approximately one-third of the height of the shaped block. 3. The outer V-belts of the plurality of V-belts have a smaller elongation elastic modulus.
The multiple V-belt type continuously variable transmission described in .